• State Resolved
  • Locked Locked
  • Replies 3 replies
  • Subscribers 33 subscribers
  • Views 312 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TCAN4550-Q1: Pin usage

Kevin SHIN
Prodigy 495 points
Part Number: TCAN4550-Q1

Hi team,

I have some questions about TCAN4550-Q1.

1. When VIO pin is controlled by MCU directly, is it okay usage status of pin as the below?

   - RST : use

   - INH, nWKRQ, GPIO1, GPIO2 : not use

2. When SPI pins connect to CPU and RST pin connects to MCU, is there any problem for this?

Thank you.

Best Regards,

Kevin Shin  

  • 0
    TI__Guru 60112 points

    Kevin,

    Thanks for bringing these questions to E2E.

    1. Yes, this should be okay, but how is the TCAN4550-Q1 indicating to the MCU that it has awakened from sleep mode? Typically this is done through nWKRQ directly to the MCU or INH enabling a power supply for VIO and/or VCC.
    2. No, this is how a typical application would connect to these pins. Is there something specific you are worried about?

    Please let me know if you have any other questions as well.

    Regards,

  • 0 in reply to Eric Hackett
    TI__Prodigy 495 points

    Hi Eric,

    Thank you for your reply.

    And customers have some more detail questions about it.

    1. They used TJA1042 of NXP that didn't have sleep/wake up function previous H/W as the below 1.

    But they wanted to change concept as the below 2 that TCAN4550-Q1 is directly connected to CPU with SPI.

    So is there any device that can communicate with CPU directly and there is no sleep/wake function?

    1. TJA1042T/3/1  <-(CAN I/F)->  MCU  – (SPI)->  CPU
    2. TCAN4550-Q1  <– SPI ->  CPU

     

    2. If CAN devices have feasiblity to use number 2 concept, is it possible to connect as the below 2 cases?

    Case 1) SPI is connected to CPU, RST is connected to MCU

    Case 2) SPI and RST pins are connected to CPU

     

    3. When GPIO of CPU(Initial status = Low) is connected to RST pin, is there any problem to reset TCAN4550-Q1device?

    - I think if timing for RST pin is correct as the below graph, there is no problem about this. Is that right?


     

    Thank you in advance.

     

    Best Regards,

    Kevin Shin

  • 0 in reply to Kevin SHIN
    TI__Guru 60112 points

    Kevin,

    Glad I could help, here are some more answers :).

    1. It will depend on what kind of functionality the customer needs. Do they need to have a CAN controller and transceiver integrated and controlled through SPI? Or do they just want a CAN transceiver that can be controlled through SPI? If it's just the transceiver, we are currently developing devices that will achieve this and should be sampling before the end of the year. If the customer needs the CAN controller integrated as well, the TCAN4550-Q1 is the only option right now and it will work when directly connected to the CPU through SPI. In all cases the device will have sleep/wake function though. Is the customer worried about the device going to sleep mode?
    2. Both cases are technically possible, but a the processing done by the CPU with the TCAN4550-Q1 register information will still need to be passed to the MCU that is controlling the RST pin. Except for the cases where a TCAN4550-Q1 reset needs to occur that doesn't involve the TCAN4550-Q1 conditions. Case 2 is feasible as well.
    3. The RST pin needs to be pulsed high to reset the TCAN4550-Q1, so if it is low on power-up it should have no effect. Was this your question?

    Regards,